Regarding the plugging mains voltage into Ethernet /specifically/....
A good ethernet-enabled device should have isolation transformers (usually referred to as "magnetics"), either in the jack or as a separate component on the board.
Long story short, it's very possible that if anything, you'd only destroy the magnetics, which while labor intensive to replace (lots of pins on a large component body!), aren't particularly expensive.
A good ethernet-enabled device should have isolation transformers (usually referred to as "magnetics"), either in the jack or as a separate component on the board.
Long story short, it's very possible that if anything, you'd only destroy the magnetics, which while labor intensive to replace (lots of pins on a large component body!), aren't particularly expensive.